diff options
author | Guo Ren <guoren@linux.alibaba.com> | 2020-05-13 10:15:25 +0300 |
---|---|---|
committer | Guo Ren <guoren@linux.alibaba.com> | 2020-05-13 12:55:06 +0300 |
commit | 18c07d23da5a48525b2955aa269b8bb108c19300 (patch) | |
tree | 450a798836c2658ff1a2b7fce73bbc5bd59df9af /arch/csky/kernel | |
parent | 229a0ddee1108a3f82a873e6cbbe35c92c540444 (diff) | |
download | linux-18c07d23da5a48525b2955aa269b8bb108c19300.tar.xz |
csky: Fixup calltrace panic
The implementation of show_stack will panic with wrong fp:
addr = *fp++;
because the fp isn't checked properly.
The current implementations of show_stack, wchan and stack_trace
haven't been designed properly, so just deprecate them.
This patch is a reference to riscv's way, all codes are modified from
arm's. The patch is passed with:
- cat /proc/<pid>/stack
- cat /proc/<pid>/wchan
- echo c > /proc/sysrq-trigger
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Diffstat (limited to 'arch/csky/kernel')
-rw-r--r-- | arch/csky/kernel/Makefile | 2 | ||||
-rw-r--r-- | arch/csky/kernel/dumpstack.c | 49 | ||||
-rw-r--r-- | arch/csky/kernel/process.c | 31 | ||||
-rw-r--r-- | arch/csky/kernel/stacktrace.c | 176 |
4 files changed, 140 insertions, 118 deletions
diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile index fd6d9dc8b7f3..37f37c0e934a 100644 --- a/arch/csky/kernel/Makefile +++ b/arch/csky/kernel/Makefile @@ -3,7 +3,7 @@ extra-y := head.o vmlinux.lds obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o obj-y += power.o syscall.o syscall_table.o setup.o -obj-y += process.o cpu-probe.o ptrace.o dumpstack.o +obj-y += process.o cpu-probe.o ptrace.o stacktrace.o obj-y += probes/ obj-$(CONFIG_MODULES) += module.o diff --git a/arch/csky/kernel/dumpstack.c b/arch/csky/kernel/dumpstack.c deleted file mode 100644 index d67f9777cfd9..000000000000 --- a/arch/csky/kernel/dumpstack.c +++ /dev/null @@ -1,49 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. - -#include <linux/ptrace.h> - -int kstack_depth_to_print = 48; - -void show_trace(unsigned long *stack) -{ - unsigned long *stack_end; - unsigned long *stack_start; - unsigned long *fp; - unsigned long addr; - - addr = (unsigned long) stack & THREAD_MASK; - stack_start = (unsigned long *) addr; - stack_end = (unsigned long *) (addr + THREAD_SIZE); - - fp = stack; - pr_info("\nCall Trace:"); - - while (fp > stack_start && fp < stack_end) { -#ifdef CONFIG_STACKTRACE - addr = fp[1]; - fp = (unsigned long *) fp[0]; -#else - addr = *fp++; -#endif - if (__kernel_text_address(addr)) - pr_cont("\n[<%08lx>] %pS", addr, (void *)addr); - } - pr_cont("\n"); -} - -void show_stack(struct task_struct *task, unsigned long *stack) -{ - if (!stack) { - if (task) - stack = (unsigned long *)thread_saved_fp(task); - else -#ifdef CONFIG_STACKTRACE - asm volatile("mov %0, r8\n":"=r"(stack)::"memory"); -#else - stack = (unsigned long *)&stack; -#endif - } - - show_trace(stack); -} diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c index f7b231ca269a..4ad6db56c3cd 100644 --- a/arch/csky/kernel/process.c +++ b/arch/csky/kernel/process.c @@ -98,37 +98,6 @@ int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs) return 1; } -unsigned long get_wchan(struct task_struct *p) -{ - unsigned long lr; - unsigned long *fp, *stack_start, *stack_end; - int count = 0; - - if (!p || p == current || p->state == TASK_RUNNING) - return 0; - - stack_start = (unsigned long *)end_of_stack(p); - stack_end = (unsigned long *)(task_stack_page(p) + THREAD_SIZE); - - fp = (unsigned long *) thread_saved_fp(p); - do { - if (fp < stack_start || fp > stack_end) - return 0; -#ifdef CONFIG_STACKTRACE - lr = fp[1]; - fp = (unsigned long *)fp[0]; -#else - lr = *fp++; -#endif - if (!in_sched_functions(lr) && - __kernel_text_address(lr)) - return lr; - } while (count++ < 16); - - return 0; -} -EXPORT_SYMBOL(get_wchan); - #ifndef CONFIG_CPU_PM_NONE void arch_cpu_idle(void) { diff --git a/arch/csky/kernel/stacktrace.c b/arch/csky/kernel/stacktrace.c index fec777a643f1..92809e1da723 100644 --- a/arch/csky/kernel/stacktrace.c +++ b/arch/csky/kernel/stacktrace.c @@ -1,57 +1,159 @@ // SPDX-License-Identifier: GPL-2.0 -/* Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. */ #include <linux/sched/debug.h> #include <linux/sched/task_stack.h> #include <linux/stacktrace.h> #include <linux/ftrace.h> +#include <linux/ptrace.h> -void save_stack_trace(struct stack_trace *trace) +#ifdef CONFIG_FRAME_POINTER + +struct stackframe { + unsigned long fp; + unsigned long ra; +}; + +void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, + bool (*fn)(unsigned long, void *), void *arg) { - save_stack_trace_tsk(current, trace); + unsigned long fp, sp, pc; + + if (regs) { + fp = frame_pointer(regs); + sp = user_stack_pointer(regs); + pc = instruction_pointer(regs); + } else if (task == NULL || task == current) { + const register unsigned long current_sp __asm__ ("sp"); + const register unsigned long current_fp __asm__ ("r8"); + fp = current_fp; + sp = current_sp; + pc = (unsigned long)walk_stackframe; + } else { + /* task blocked in __switch_to */ + fp = thread_saved_fp(task); + sp = thread_saved_sp(task); + pc = thread_saved_lr(task); + } + + for (;;) { + unsigned long low, high; + struct stackframe *frame; + + if (unlikely(!__kernel_text_address(pc) || fn(pc, arg))) + break; + + /* Validate frame pointer */ + low = sp; + high = ALIGN(sp, THREAD_SIZE); + if (unlikely(fp < low || fp > high || fp & 0x3)) + break; + /* Unwind stack frame */ + frame = (struct stackframe *)fp; + sp = fp; + fp = frame->fp; + pc = ftrace_graph_ret_addr(current, NULL, frame->ra, + (unsigned long *)(fp - 8)); + } } -EXPORT_SYMBOL_GPL(save_stack_trace); -void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +#else /* !CONFIG_FRAME_POINTER */ + +static void notrace walk_stackframe(struct task_struct *task, + struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg) { - unsigned long *fp, *stack_start, *stack_end; - unsigned long addr; - int skip = trace->skip; - int savesched; - int graph_idx = 0; + unsigned long sp, pc; + unsigned long *ksp; - if (tsk == current) { - asm volatile("mov %0, r8\n":"=r"(fp)); - savesched = 1; + if (regs) { + sp = user_stack_pointer(regs); + pc = instruction_pointer(regs); + } else if (task == NULL || task == current) { + const register unsigned long current_sp __asm__ ("sp"); + sp = current_sp; + pc = (unsigned long)walk_stackframe; } else { - fp = (unsigned long *)thread_saved_fp(tsk); - savesched = 0; + /* task blocked in __switch_to */ + sp = thread_saved_sp(task); + pc = thread_saved_lr(task); } - addr = (unsigned long) fp & THREAD_MASK; - stack_start = (unsigned long *) addr; - stack_end = (unsigned long *) (addr + THREAD_SIZE); - - while (fp > stack_start && fp < stack_end) { - unsigned long lpp, fpp; + if (unlikely(sp & 0x3)) + return; - fpp = fp[0]; - lpp = fp[1]; - if (!__kernel_text_address(lpp)) + ksp = (unsigned long *)sp; + while (!kstack_end(ksp)) { + if (__kernel_text_address(pc) && unlikely(fn(pc, arg))) break; - else - lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL); - - if (savesched || !in_sched_functions(lpp)) { - if (skip) { - skip--; - } else { - trace->entries[trace->nr_entries++] = lpp; - if (trace->nr_entries >= trace->max_entries) - break; - } - } - fp = (unsigned long *)fpp; + pc = (*ksp++) - 0x4; } } +#endif /* CONFIG_FRAME_POINTER */ + +static bool print_trace_address(unsigned long pc, void *arg) +{ + print_ip_sym(pc); + return false; +} + +void show_stack(struct task_struct *task, unsigned long *sp) +{ + pr_cont("Call Trace:\n"); + walk_stackframe(task, NULL, print_trace_address, NULL); +} + +static bool save_wchan(unsigned long pc, void *arg) +{ + if (!in_sched_functions(pc)) { + unsigned long *p = arg; + *p = pc; + return true; + } + return false; +} + +unsigned long get_wchan(struct task_struct *task) +{ + unsigned long pc = 0; + + if (likely(task && task != current && task->state != TASK_RUNNING)) + walk_stackframe(task, NULL, save_wchan, &pc); + return pc; +} + +#ifdef CONFIG_STACKTRACE +static bool __save_trace(unsigned long pc, void *arg, bool nosched) +{ + struct stack_trace *trace = arg; + + if (unlikely(nosched && in_sched_functions(pc))) + return false; + if (unlikely(trace->skip > 0)) { + trace->skip--; + return false; + } + + trace->entries[trace->nr_entries++] = pc; + return (trace->nr_entries >= trace->max_entries); +} + +static bool save_trace(unsigned long pc, void *arg) +{ + return __save_trace(pc, arg, false); +} + +/* + * Save stack-backtrace addresses into a stack_trace buffer. + */ +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + walk_stackframe(tsk, NULL, save_trace, trace); +} EXPORT_SYMBOL_GPL(save_stack_trace_tsk); + +void save_stack_trace(struct stack_trace *trace) +{ + save_stack_trace_tsk(NULL, trace); +} +EXPORT_SYMBOL_GPL(save_stack_trace); + +#endif /* CONFIG_STACKTRACE */ |